External weft fed loom and a shuttle therefor

ABSTRACT

In an external weft fed loom, a shuttle and a circuit for delivering same to and from a shed in which said circuit includes a conduit having a pair of curvilinear portions and a pair of rectilinear portions and in which said shuttle has portions of its external surfaces contoured to conform to said curvilinear portions and portions contoured to conform to said rectilinear portions and is of such a height with respect to said conduit so that impacting of said shuttle in said conduit when said shuttle traverses said conduit is eliminated.

United States Patent Moessinger [451 Oct. 10,1972

1541 EXTERNAL WEFT FED LOOM AND A SHUTTLE THEREFOR [72] Inventor: Albert E. Moessinger, 1 Grand Place, Fribourg, Switzerland [22] Filed: Jan. 12, 1970 [21] Appl. N0.: 2,174

[52] US. Cl ..l39/125 [51] Int. Cl. ..D03d 47/24, D03j 5/06 [58] Field of Search ..l39/122, 125, 127,116

[56] References Cited UNITED STATES PATENTS 3,310,072 3/1967 Strobl ..139/125 3,378,041 4/1968 Moessinger ..139/125 FOREIGN PATENTS OR APPLICATIONS France ..139/125 France ..l39/125 France 1 39/1 25 Primary Examinerl-Ienry S. Jaudon Attorney-Sherman and Shalloway [57] ABSTRACT In an external weft fed loom, a shuttle and a circuit for delivering same to and from a shed in which said circuit includes a conduit having a pair of curvilinear portions and a pair of rectilinear portions and in which said shuttle has portions of its external surfaces contoured to conform to said curvilinear portions and portions contoured to conform to said rectilinear portions and is of such a height with respect to said conduit so that impacting of said shuttle in said conduit when said shuttle traverses said conduit is eliminated.

11 Claims, 8 Drawing Figures Pmmtnw 10 m2 SHEET 1 [IF 2 INVENTOR ALBERT E. M ESSINGER ATTORNEYS PATENIEUnm 10 m2 SHEET E OF 2 lNV ENTOR ALBERT E M0555 INQE/f ATTORNEYS EXTERNAL WEFI FED LOOM AND A SHUTTLE THEREFOR BACKGROUND OF THE INVENTION External weft fed looms wherein the shuttle circulates continuously in a closed circuit generally have a shuttle passage exhibiting variable radii of curvature. Most frequently, the passage comprises two semi-circular conduits spaced apart and interconnected by straight conduits extending in prolongation of the semicircular conduits. The shuttles, which circulate during their entire travel at velocities as great as 30 m/second, must be guided with great exactitude in order to avoid shocks and impacts which cause wear and noise.

In general, the designers of these looms have started from the conventional shape of the shuttles and have adapted the dimensions of the passage to that shape. These shuttles, which are of prismatic shape and have at least one end pointed, require a conduit or passage height which is greater in the curved portions than in the straight portions. Transition from the straight portions to the curved portions necessitates a variableheight adjustment connecting the two conduits of a different height in a clearly determined manner. If such height profiling is not provided in an extremely precise manner, the result will be impacts during the passage of the shuttle, thus causing noise and wear.

It has already been proposed to employ a shuttle having the shape of a segment of a disc and, in this case, the rectilinear and curvilinear conduits may have the same height, thus greatly facilitating design and construction. However, apart from the fact that friction takes place at one side of the shuttle between a cylindrical surface and a plane, and thus on a generatrix which will rapidly become worn, this shape. of shuttle does not make it possible to avoid impacts and shocks on passage from a rectilinear tangential conduit to a curvilinear conduit. In fact, although the center of gravity of the shuttle follows a movement without sudden variation, the same is not true of the rotation of the shuttle about its center of gravity which changes suddenly from a certain value (zero when the conduit is rectilinear) to a further value proportional to V/R, V being the velocity of the shuttle and R the radius of curvature of the semi-circular conduit. It will be ap- SUMMARY OF THE INVENTION This invention relates to an external weft fed loom and a shuttle therefor. According to one aspect of the invention there is provided an external weft fed loom which includes a conduit having both curvilinear sections and straight elongated sections which together constitute a circuit for delivering a shuttle to and from a shed.

According to another aspect of the invention, there is provided a shuttle for an external weft fed loom, such shuttle having curved surface portions disposed along its length on either side of its center of gravity, the curved portions of the shuttle corresponding to curved portions of curvilinear section of a conduit of the loom which forms a circuit for delivering the shuttle to and from a shed.

BRIEF DESCRIPTION OF THE DRAWINGS Illustrative embodiments of the invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 illustrates a cross-sectional view of 'one form of loom;

FIG. 2 illustrates a shuttle passing from a rectilinear path to a curved path;

FIG. 3 illustrates one form of shuttle suitable for circulating in the path shown in FIG. 4;

FIG. 4 illustrates one form of continuous path;

FIGS. 5-7 illustrate one form of shuttle gripper device; and

FIG. 8 illustrates an arrangement for reducing friction during the curve portions of travel of a shuttle in a continuous path for the shuttle.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1 there is shown a loom having a frame 40, 41 on which are mounted casings 42 and 43 each containing a pair of meshing bevel gears 44, 45 with one pair of gears connected with and driven by a pulley 46 which also drives the loom via a main shaft 47. Gears 45 are connected respectively to discs-48, 49 for driving a pair of identical shuttles 50.

The disc 48 is arranged to receive a shuttle from a return conduit 52 and pick it into a conduit 53 whereupon it is subsequently ejected into the shed formed by warp threads 54 passing through a reed 55. The disc 48 is called the picking disc. After passage through the shed, the shuttle passes into the conduit 56, to be received on the disc 49, known as the take-up disc. A sley moved by an arm 57 carries the reed 55 and is actuated by two sets of cams 58, 59 mounted on the main shaft 47, through the intermediary of levers 60.

On travelling through the conduit 53, the shuttle engages the thread 61 drawn from a bobbin 62 fixed by known means (not shown) and draws it into the shed. On leaving the shed, the thread 61 is freed from the shuttle, again by known means, and is retained by a suction force coming from a nozzle 63 in such manner that it does not re-enter the shed.

In this type of loom, the passage of the shuttle between two portions of the conduit having different radii of curvature has always involved difficulty. In

order to obviate these difficulties, the opposite faces of the shuttle are formed into surfaces having radii of curvature corresponding to those of the conduits. The outer face or side (see FIG. 2) is constituted at its ends by two arcuate surfaces 4 and 5 on the trailing and leading ends, respectively, having a raduis R2, whereas a central portion of the body of the shuttle has a planar outer surface 6. The inner face or side is constituted, at the trailing and leading ends, by two planar surfaces 7 and 8, respectively, which are parallel to the surface 6 and spaced away from'the latter by the thickness (E e) of the shuttle, whereas the central median portion has an arcuate inner surface 9 of radius R1, concentric with R2, and spaced therefrom by the value (E e). The value E represents the height of the guide conduit and e the clearance necessary for the displacement of the shuttle in the conduit, with minimum resistance.

In the embodiment of FIG. 2, the shuttle 50 is shown in dotted lines at the instant at which its movement commences to be influenced by a curvilinear guiding portion of a conduit and in full lines at the instant at which its movement is under the full influence of the curvilinear guiding portion.

The length l of the median portion face, which also represents the distance between corresponding points of the dotted line and full line positions of shuttle 50 shown in FIG. 2, has intentionally been chosen to be as large as possible to prevent sudden rotation of the shuttle between the rectilinear portion 2 and the curvilinear portion 3 of the guide conduit. In fact, the shuttle will, in the position shown in dotted lines, undergo uniform rectilinear movement without rotation about its center of gravity. However, starting from its position 1', wherein it is shown in full lines, the shuttle will undergo uniform curvilinear movement about the center of the radii of curvature of the conduit 3 and its center of gravity 10 will follow a circle of radius Rx at a velocity wRx while the shuttle rotates aboutits center of gravity at the constant angular velocity (0. During the displacement of the shuttle 50 between the two positions shown over the length 1, its movement of rotation about its center of gravity passes from to w. The forces necessary for this change in velocity, which forces are obtained from the curvilinear. guiding portion, will increase proportionally with a decrease in the length 1. Thus, by selecting a high value for 1 two important advantages are obtained. Firstly, the pressures exerted by the shuttle on the curved portions of the conduit are diminished; and, secondly, the pressures are distributed over a greater length of the conduit. Thus, local wear which would cause an uneven passage for the shuttle is avoided.

FIG. 3 illustrates a form of the shuttle 50. The profile of shuttle 50 is determined in the following manner. Two circles 15 having a diameter (E 6) corresponding to the height E of the conduit minus the clearance e necessary for satisfactory travel of the shuttle, are disposed at a distance I from each other. Tangentially to these two circles 15, there are drawn circles 16 and 17, the radii of which correspond to the radii of curvature R3 and R4-of the surfaces of one portion of the conduit, and circles 18 and 19, the radii of which correspond to the radiiof curvature R5 and R6 of the other portion of the conduit. The surface remaining within these curves (the hatched surface) represents the profile of the shuttle wherein it is still possible to adapt the leading end so that it will pass between the warp threads, and the trailing end in order that it will receive the pulses which maintain its movement. A shuttle of this shape will be able to travel without shock and impact and without detrimental play or clearance in a passage of constant height having the shape shown.

in FIG. 4.

FIGS. 5, 6, and 7 show an adaptation of the shuttle for a gripper type loom having a gripper member of especially advantageous shape. The body of the shuttle 20 has, rearwardly of its outer face, a transverse notch 21 milled therein at a predetermined angle. A lengthwise groove 22 of rectangular section extends longitudinally along the entire inner face of the shuttle to a rear portion 23 and an area 24 on the external face, external of the shuttle. Groove 22 communicates at an even level. with the bottom of the notch 21. Disposed in the grooves 22, 23, and 24 is a lamella 25 made of spring steel curved at the rear and riveted towards the from point of the shuttle by means of a rivet 26. The curved portion of the lamella 25 forms the gripper member 27 which bears precisely on the bottom of the notch 21 and of. the groove 24 and forms a gripper member for retaining the weft thread. The notch 21 terminates on each side of the shuttle in rounded surfaces 211 on which the gripped thread'6l is applied. A cam 28 fixed in the shuttle guide means urges the lamella 25 upwardly against said shuttle and opens the gripper member 27 which then projects from the profile of the shuttle and engages the thread presented to it in its pathway, subsequently releasing the thread after having drawn it through the shed. ln FIGS. 5, 6, and 7, the guide conduit for the shuttle has been shown in broken lines so as to show the aperture 29 through which the thread to be engaged by the shuttle extends in tension.

It will be clear that, considering the clearances necessary for the movement of the shuttle, the surfaces of the shuttle may have small variations relatively to the corresponding surfaces of the guide conduit. For example, the radius of curvature of an arcuate surface of the shuttle may deviate from the radius of curvature of the arcuate surface of the guideway on which it exerts frictional action by the amount of the value 6 corresponding to the play or clearance of the shuttle in the guideway. Furthermore, in order to facilitate the sliding of the surfaces relatively to each other, it is frequently useful to provide a small angle between the direction of movement and the moving surface. In order to obtain this result, it is possible to provide arcuate surfaces 33, 34, 35, and 36 the radius of curvatures of which are similar but which are slightly eccentric relative to the radii R7 and R8 of the guideway, as shown in FIG. 8. Of course, the angle formed between the associated surfaces is extremely small and is a function of the state of the guide surfaces; that is, if an oil film is permissible or if a cushion of air acts as a lubricating means, the angle will be affected.

Similarly, the plane surfaces 30, 31, and 32 may also form a small angle with the guide surfaces 37, 38 and consequently they may no longer be exactly parallel to each other. This deviation is tolerated only within the infinitely small limits compatible with aerodynamic (or hydrodynamic) action of the moving surfaces.

With regard to the passage in which the shuttle circulates, it will be necessary to avoid any discontinuity in the surfaces guiding the shuttle. Thus, continuity between the rectilinear conduit and the lower portion of the curvilinear conduit, when the latter is formed by a wheel, is frequently rendered difiicult in view of the radius R of the wheel and the clearance j necessary between the fixed member and the moving sheel (F IG. 9). The result is a length a on which guiding is interrupted, and this length may be greater than the length of the surface 8 of the shuttle (FIG. 2).

What is claimed is:

1. A shuttle for use with an external weft fed loom having circuit conduit means defining a path of travel for said shuttle and including a curvilinear portion defined by an inner wall having a first radius of curvature and an outer wall having a second radius of curvature greater than the first radius of curvature, and a rectilinear portion tangentially connected with the curvilinear portion, said shuttle comprising a body including a central portion having a first inner surface and a first outer surface, a leading end extending from said central portion and having a second inner surface and a second outer surface and a trailing end extending from said central portion opposite said leading end and having a third inner surface and a third outer surface, said first inner surface having a radius of curvature substantially the same as the first radius of curvature of the inner wall of the curvilinear portion of the circuit conduit means, said second and third outer surfaces each having a radius of curvature substantially the same as the second radius of curvature of the outer wall of the curvilinear portion of the circuit conduit means, and said first outer surface and said second and third inner surfaces being planar.

2. A shuttle as recited in claim 1 wherein the rectilinear portion of the circuit conduit means is defined by spaced inner and outer walls, said first outer surface being spaced from said second and third inner surfaces slightly less than the space between the inner and outer walls of the rectilinear portion of the circuit conduit means.

3. A shuttle as recited in claim 2 wherein said second and third inner surfaces are aligned and disposed in parallel relation with said first outer surface.

4. A shuttle as recited in claim 3 wherein said central portion has a length at least equal to the length of each of said leading and trailing ends.

5. A shuttle as recited in claim 4 wherein the circuit conduit means has a constant height, said shuttle being provided with a profile defined by said first inner surface disposed tangentially with circles disposed at the points of connection between said leading and trailing ends and said central portion of said body and by said second and third outer surfaces disposed tangentially with said circles, said circles having a diameter substantially equal to the height of the circuit conduit means.

6. A shuttle as recited in claim 1 wherein said central portion has a length at least equal to the length of each of said leading and trailing ends.

7. A shuttle as recited in claim 1 wherein the circuit conduit means has a constant height, said shuttle being provided with a profile defined by said first inner surface disposed tangentially with circles disposed at the points of connection between said leading and trailing ends and said central portion of said body and by said second and third outer surfaces disposed tangentially with said circles, said circles having a diameter substantially equal to the height of the circuit conduit means.

8. In an external weft fed loom, the combination comprising circuit conduit means defining a path of travel for said shuttle and including a pair of oppositely disposed curvilinear portions each defined by an inner wall having a first radius of curvature and an outer wall having a second radius of curvature greater than said first radius of curvature and a pair of parallel rectilinear portions tangentially interconnecting said curvilinear portions and formed by spaced inner and outer walls, and a shuttle including a body including a central portion having a first inner surface and a first outer surface, a leading end extending from said central portion and having a second inner surface and a second outer surface, and a trailing end extending from said central rtion o ite said .leadin end and havi a third iii iier surf c and a third out r surface, said irst inner surface having a radius of curvature substantially the same as said first radius of curvature of said inner wall of said curvilinear portions of said circuit conduit means and said second and third outer surfaces each having a radius of curvature substantially the same as said second radius of curvature of said outer wall of said curvilinear portions of said circuit conduit means.

9. The combination as recited in claim 8 wherein said first outer surface is planar, said second and third inner surfaces are planar and spaced from said first outer surface slightly less than the space between said inner and outer walls of said rectilinear portions, said second and third inner surfaces being aligned and disposed in parallel relation with said first outer surface, and said central portion has a length at least equal to the length of each of said leading and trailing ends.

10. A shuttle for use with an external weft fed loom comprising a body having first and second opposing sides and including a central portion having first and second guide surfaces, a leading end extending from said central portion having third and fourth guide surfaces, and a trailing end extending from said central portion opposite said leading end and having fifth and sixth guide surfaces, said first guide surface having a curved configuration and being disposed on said first side of said body, said third and fifth guide surfaces each having a curved configuration and being disposed on said second side of said body, said second guide surface having a planar configuration and being disposed on said second side of said body, and said fourth and sixth guide surfaces having planar configurations and being disposed on said first side of said body in parallel relation with said second guide surface.

11. A shuttle as recited in claim 10 wherein said first guide surface has a first radius of curvature and said third and fifth guide surfaces each have a second radius of curvature greater than said first radius of curvature, said first guide surface being concentric with said third and fifth guide surfaces. 

1. A shuttle for use with an external weft fed loom having circuit conduit means defining a path of travel for said shuttle and including a curvilinear portion defined by an inner wall having a first radius of curvature and an outer wall having a second radius of curvature greater than the first radius of curvature, and a rectilinear portion tangentially connected with the curvilinear portion, said shuttle comprising a body including a central portion having a first inner surface and a first outer surface, a leading end extending from said central portion and having a second inner surface and a second outer surface and a trailing end extending from said central portion opposite said leading end and having a third inner surface and a third outer surface, said first inner surface having a radius of curvature substantially the same as the first radius of curvature of the inner wall of the curvilinear portion of the circuit conduit means, said second and third outer surfaces each having a radius of curvature substantially the same as the second radius of curvature of the outer wall of the curvilinear portion of the circuit conduit means, and said first outer surface and said second and third inner surfaces being planar.
 2. A shuttle as recited in claim 1 wherein the rectilinear portion of the circuit conduit means is defined by spaced inner and outer walls, said first outer surface being spaced from said second and third inner surfaces slightly less than the space between the inner and outer walls of the rectilinear portion of the circuit conduit means.
 3. A shuttle as recited in claim 2 wherein said second and third inner surfaces are aligned and disposed in parallel relation with said first outer surface.
 4. A shuttle as recited in claim 3 wherein said central portion has a length at least equal to the length of each of said leadinG and trailing ends.
 5. A shuttle as recited in claim 4 wherein the circuit conduit means has a constant height, said shuttle being provided with a profile defined by said first inner surface disposed tangentially with circles disposed at the points of connection between said leading and trailing ends and said central portion of said body and by said second and third outer surfaces disposed tangentially with said circles, said circles having a diameter substantially equal to the height of the circuit conduit means.
 6. A shuttle as recited in claim 1 wherein said central portion has a length at least equal to the length of each of said leading and trailing ends.
 7. A shuttle as recited in claim 1 wherein the circuit conduit means has a constant height, said shuttle being provided with a profile defined by said first inner surface disposed tangentially with circles disposed at the points of connection between said leading and trailing ends and said central portion of said body and by said second and third outer surfaces disposed tangentially with said circles, said circles having a diameter substantially equal to the height of the circuit conduit means.
 8. In an external weft fed loom, the combination comprising circuit conduit means defining a path of travel for said shuttle and including a pair of oppositely disposed curvilinear portions each defined by an inner wall having a first radius of curvature and an outer wall having a second radius of curvature greater than said first radius of curvature and a pair of parallel rectilinear portions tangentially interconnecting said curvilinear portions and formed by spaced inner and outer walls, and a shuttle including a body including a central portion having a first inner surface and a first outer surface, a leading end extending from said central portion and having a second inner surface and a second outer surface, and a trailing end extending from said central portion opposite said leading end and having a third inner surface and a third outer surface, said first inner surface having a radius of curvature substantially the same as said first radius of curvature of said inner wall of said curvilinear portions of said circuit conduit means and said second and third outer surfaces each having a radius of curvature substantially the same as said second radius of curvature of said outer wall of said curvilinear portions of said circuit conduit means.
 9. The combination as recited in claim 8 wherein said first outer surface is planar, said second and third inner surfaces are planar and spaced from said first outer surface slightly less than the space between said inner and outer walls of said rectilinear portions, said second and third inner surfaces being aligned and disposed in parallel relation with said first outer surface, and said central portion has a length at least equal to the length of each of said leading and trailing ends.
 10. A shuttle for use with an external weft fed loom comprising a body having first and second opposing sides and including a central portion having first and second guide surfaces, a leading end extending from said central portion having third and fourth guide surfaces, and a trailing end extending from said central portion opposite said leading end and having fifth and sixth guide surfaces, said first guide surface having a curved configuration and being disposed on said first side of said body, said third and fifth guide surfaces each having a curved configuration and being disposed on said second side of said body, said second guide surface having a planar configuration and being disposed on said second side of said body, and said fourth and sixth guide surfaces having planar configurations and being disposed on said first side of said body in parallel relation with said second guide surface.
 11. A shuttle as recited in claim 10 wherein said first guide surface has a first radius of curvature and said third and fifth guide surfaces each have a second radius of curvature greater than said first radiuS of curvature, said first guide surface being concentric with said third and fifth guide surfaces. 